Driving arrangement for an electric watch

ABSTRACT

An electric watch including an electro-mechanical converter driven by a signal produced by dividing a series of divider means, a relatively high frequency oscillating time standard signal. The output of the last of said divider means is combined in a wave shaping logic circuit with the output of an intermediate stage of said divider means for producing a pulse signal for application to an electro-mechanical converter, the width of the pulses of which is determined by the period of said intermediate stage output.

will? States atent [191 Hanna July 3, 1973 [54] DRIVING ARRANGEMENT FOR AN 3,553,957 l/l97l Dome et al. 58/23 A ELECTRIC WATCH 3,534,544 10/1970 Oguey et al 58/23 A Inventor: Tetsuro llama, Suwa, Japan Foreign Application Priority Data July 27, 1970 Japan 45/65033 U.S. Cl. 58/23 A, 318/107 Int. Cl G04c 3/00 Field of Search 58/23 R, 23 A;

References Cited UNITED STATES PATENTS 3,363,410 1/1968 Imahashi 58/34 Primary Examiner-Richard B. Wilkinson Assistant Examiner-Edith C. Simmons .lackmon A ttorney- Alex Friedman, Harold 1. Kaplan et al.

[ 57] ABSTRACT An electric watch including an electro-mechanical converter driven by a signal produced by dividing a series of divider means, a relatively high frequency oscillating time standard signal. The output of the last of said divider means is combined in a wave shaping logic circuit with the output of an intermediate stage of said divider means for producing a pulse signal for application to an electro-mechanical converter, the width of the pulses of which is determined by the period of said intermediate stage output.

4 (Ilaims, 7 Drawing Figures lSez.

PATENTEDJULB I9 3 3.742.697 SHEEI 0F 4 FIG. 6

TETSURO HAMA 2&0, 7M H 11% ATTORNEYS DRIVING ARRANGEMENT FOR AN ELECTRIC WATCH BACKGROUND OF THE INVENTION This invention relates to an electric watch wherein an electro-mechanical converter is driven by an alternatingpulse signal. In such watches a standard signal, such as the output of a crystal vibrator having a relatively high oscillating frequency is divided into low frequencies by divider circuits and wave shaping circuits. In the art, such circuits have generally consisted of flip-flops and monostable multi-vibrators incorporating resistive and capacitive components, which have occupied a large space, and have caused problems in reliability, difficulties which are particularly troublesome in wrist watches. By the utilization of field effect type transistors (FET) assemblied using integrated circuits (IC) techniques, the foregoing disadvantages have been avoided.

SUMMARY OF THE INVENTION Generally speaking, in accordance with the invention, the wave shaping circuitry utilized to shape the divided output of the crystal oscillator of an electric watch is formed from logic circuitry formed from field effect transistors utilizing integrated circuit techniques, without the use of resistive or capacitive elements. Specifically, a series of divider means are utilized to divide the output of the crystal oscillator, and a wave shaping logic circuit means combines the output of the last of said divider means with the output of an intermediate stage of said divider means to produce an alternating pulse driving signal for an electro-mechanical converter, the width of said pulse being determined by the period of the output of said intermediate divider means stage.

Accordingly, one object of the invention is to provide a driving circuit for a quartz crystal wrist watch and the like using a direct coupled type of logic circuit.

Another object of the invention is to provide an electric watch utilizing highly reliable integrated circuits including MOS FETs.

Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.

The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims.

BRIED DESCRIPTION OF THE DRAWINGS For a fuller understanding of the invention, reference is had to the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a circuit diagram showing a conventional type of driving circuit for a quartz crystal watch and the like FIG. 2 is a circuit and schematic diagram showing the electro-mechanical converter driving circuit according to the invention;

FIG. 3 is a wave form diagram showing the wave forms of the signals applied to the driving circuit of FIG. 2;

FIG. 4 is a block diagram showing the divider and wave shaping circuits according to the invention;

FIG. 5 is a circuit diagram of the wave shaping circuits of FIG. 4;

FIG. 6 is a circuit diagram of part A of FIG. 5; and

FIG. 7 is a wave form diagram showing the wave forms of the signals of the circuit of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS I Referring to FIG. 1, the conventional driving arrangement for an electric watch depicted includes a flip-flop circuit FF supplied by a one second signal. Each of the outputs of said flip-flop circuit is connected to a monostable multi-vibrator MV and MV which are alternately triggered from the left and right side of the flip-flop. Said multi-vibrators form the signal into a predetermined pulse width which is applied to the bases of a pair of complementary driving transistors. In the art, both the flip-flop and the monostable multivibrators incorporate resistive and capacitive elements. The foregoing arrangements produces a driving current flowing alternately through coils L and L of an electro-mechanical converter.

To produce driving pulses of 15 milliseconds width, said monostable multi-vibrators must incorporate high value resistors having a resistance of about 10 M9 and high value capacitors of about 1,500 PF. Such resistors and capacitors occupy too large a portion of the space available in a wrist watch, and the wiring projecting from such electrical component results in relatively low reliability.

Referring now to FIG. 2, one embodiment of a pulse motor according to the invention is shown coupled to a driving circuit. The pulse motor of FIG. 2 is shown by way of example, other types of electro-mechanical converters being equally applicable to the electric watch according to the invention. In said pulse motor, a rotor l is provided formed with a permanent magnet having six poles. Said rotor rotates in the field ofa yoke 2 having coils 3 wound about legs thereof. The rotation of the rotor is transmitted to a wheel 4 which drives a second hand 5. Bipolar transistors 6 and 7 of the PNP type are coupled with bipolar transistorsS and 9 of the NPN type to form a driving circuit. Bipolar type transistors are used for this application instead of the MOS transistors, in view of the current which must be carried thereby. Driving signals consisting of inputs 1, 2, 3 and 4 are applied respectively to the bases of driving transistors 6, 7, 8 and 9. Said driving transistors are coupled as complementary pairs and the input signals are adapted such that alternating pulses of a width 1,, are applied to coil 3 every second.'Thus, the driving signal is appliedto transistors 6 and 8 at the same time to apply a pulse in one direction to coil 3, and then a driving signal is applied to transistors 7 and 9 to apply a driving current to coil 3 in the opposite direction. t,, is generally selected to be 15 milliseconds.

The wave forms of the inputs applied to said driving circuit is shown in FIG. 3. Inputs 1 and 2 are of positive potential but their potentials become zero only when the pulse of t,, width is applied to coil 3. Inputs 3 and 4 correspond to and are the reverse of the signals of input 1 and 2. The wave forms of inputs 1 and 3 are shifted by one second as compared with the wave forms of inputs 2 and 4.

The signals of inputs 1, 2, 3 and 4 are applied to the driving circuit with a time delay of r in the worst case after a resetting signal is applied by resetting means from outside the circuit.

A crystal oscillator of the quartz crystal watch according to our invention has 16,385 kHz of frequency. This signal is divided into 2 second signal by lS-stage flip-flop circuit.

In the quartz crystal watch according to our invention, the resetting mechanism is provided in order to set a watch by standard time. When all circuits of lS-stage divider circuit are resetted, it is favorable if they are held. The resetting circuit is not provided in flip-flop circuit from the first stage to 8 stage, and it is provided in flip-flop circuit from 9 stage to 15 stage because the resetting circuit is complicated, 8-stage signal is 64 Hz and when the reset switch provided in the watch case is cut off and the. watch starts, the value of time delay td which is shifted from the standard time is very small, so it is convenient for the user of the watch. Therefore, the value of rd has not a direct relation with the inventive thought of the present invention.

Referring now to the block diagram of FIG. 4, the time standard signal source F is divided into a one second signal by a series of divider flip-flop circuits F F F,,, F,.. The outputs of flip-flops F and F, are applied to wave shaping circuits A, B and C to produce input signals 1, 2, 3 and 4 depicted in FIG. 3.

Shaping circuit A serves to delay input signal F, by the pulse width of input signal F,,. The signal P, is an alternating signal reversed every other second, and is the output of a flip-flop having a two second period. The signal F,, is the output signal of a flip-flop having a pulse width of one-sixtyforth of a second. Accordingly, shaping circuit A serves to delay the wave form F, with its two second period by one sixty-fourth second from the initial signal. Shaping circuits B and C receive the signal from shaping circuit A, the signal F, with its 2 second period, and the signal F a signal which is 180 out of phase with F Shaping circuit B includes a NAND gate while shaping circuit C includes a NOR gate, said circuits being adapted to produce the input signals depicted in FIG. 3.

FIG. 5 shows the circuit diagrams of shaping circuits A, B and C, which utilize MOS FET integrated circuits. Thus, by use of the techniques of large-scale integrated circuits, the entire circuitry can be assemblied in a very small-sized device which is extremely reliable, and particularly adapted for mass production. As seen in FIG. 5, the left half side of shaping circuit B includes said NAND gate, while the right hand side thereof includes an inverter circuit. Similarly, shaping circuit C includes, in its left hand side, a NOR gate, and in its right hand side an inverter circuit.

Accordingly, without using either resistive or capacitive elements, any pulse width can be obtained in the circuit according to the invention by merely shifting F to F,, or F 7 As shown in FIG. 6, part A of FIG. 5 includes a transmission gate with terminals 1, 2 and 3 served as transfer switch, a NAND circuit 4 and an inverter. By the transmission gate, Fx (2 second signal) is put in terminal 1, and Fn and F5 (32 Hz) are put in terminal 3. Output signal FxD can obtain output signal which is delayed tm as shown in FIG. 7.

When Fx and FxD are supplied to AND circuit, the signal of input 3 is formed as shown in upper part B of FIG. 5. When F xand FxD are supplied to AND circuit, the signal of input 4 is formed as shown in lower part B of FIG. 5. Moreover, the signals of input I and 2 are formed at part C of FIG. 5 based on the following equation, wherein the-signal ofinput 1 is Fx'FI.

As the same way, the signal of input 2 can be obtained as follows: i

The transistor employs an enhancement type of Metal-Oxide-Semiconduct Field Effect Transistor (MOS- FET). N-channel MOST makes on when the voltage of the gate electrode is made high level, and P-channel MOST makes on when the voltage of the gate electrode is made low level.

Further, the desired alternating pulse of ultra low frequency is obtained by connecting the output of the shaping circuits according to the invention with four transistors as shown in FIG. 2. In this manner, the pulse motor of FIG. 2 can be driven to produce a high quality quartz crystal electric watch.

It will thus be seen that the objects set forth above, and those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above constructions without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebe tween.

What is claimed is:

1. An electric watch comprising a crystal oscillator oscillating at a relatively high frequency; a DC source having a pair of terminals; a stepped motor; and circuit means for applying an alternating driving signal to said stepped motor derived from the output of said crystal oscillator including frequency divider and wave shaping circuit means formed from MOS transistors and driving circuit means for applying said driving signal to said stepped motor in response to the signals from said wave shaping circuit means, said driving circuit means including two pairs of switching means, each of said pairs being connected in series with said stepped motor between said DC source terminals, said wave shaping circuit means being directly coupled to said switching means without capacitors.

2. An electric watch comprising an electromechanical converter; means for producing a relatively high frequency oscillating time standard signal; a plurality of divider means coupled to said time standard means for producing at its output stage a signal of relatively low frequency; and wave form shaping circuit means coupled to said divider means for receiving the output signal of said last divider means stage and of an intermediate divider means stage, and coupled to said electro-mechanical converter for applying an alternating pulse signal thereto of a pulse width representative of the pulse width of the signal from said intermediate stage of said divider means.

3. An electric watch as recited in claim 2, wherein said wave form shaping circuit is formed from integrated circuits utilizing MOS transistors.

4. An electric watch as recited in claim 2, wherein said wave shaping circuit means is adapted to delay the output signal of the last stage of said divider means by the pulse width of the signal from said intermediate stage of said divider means.

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1. An electric watch comprising a crystal oscillator oscillating at a relatively high frequency; a DC source having a pair of terminals; a stepped motor; and circuit means for applying an alternating driving signal to said stepped motor derived from the output of said crystal oscillator including frequency divider and wave shaping circuit means formed from MOS transistors and driving circuit means for applying said driving signal to said stepped motor in response to the signals from said wave shaping circuit means, said driving circuit means including two pairs of switching means, each of said pairs being connected in series with said stepped motor between said DC source terminals, said wave shaping circuit means being directly coupled to said switching means without capacitors.
 2. An electric watch comprising an electro-mechanical converter; means for producing a relatively high frequency oscillating time standard signal; a plurality of divider means coupled to said time standard means for producing at its output stage a signal of relatively low frequency; and wave form shaping circuit means coupled to said divider means for receiving the output signal of said last divider means stage and of an intermediate divider means stage, and coupled to said electro-mechanical converter for applying an alternating pulse signal thereto of a pulse width representative of the pulse width of the signal from said intermediate stage of said divider means.
 3. An electric watch as recited in claim 2, wherein said wave form shaping circuit is formed from integrated circuits utilizing MOS transistors.
 4. An electric watch as recited in claim 2, wherein said wave shaping circuit means is adapted to delay the output signal of the last stage of said divider means by the pulse width of the signal from said intermediate stage of said divider means. 